David Barker - Quintel - Base Station Antenna Innovation

16 February 2011

Base Station Antenna Innovation and re-configurable Networks

David Barker, CTOQuintel Technology

Copyright © 2011 Quintel. All rights reserved.

Quintel Confidential.

Agenda

• Base Station Antenna Evolution

• Where now with Antennas? Space or Spectral Efficiency?

• How Quintel is innovating for Space and Spectral Efficiency

• The Smarter Antenna: Smart features but on a Passive Platform

• What’s a Dynamic Network

• Summary



Space Efficiency Techniques

Multi-array

Multi-Port

Combiners

How the Base Station Antenna has evolvedMaxwell’s Laws not Moore’s Law

Source: 3G Americas; 3G & 4G Antenna Deployment

Spectral Efficiency Techniques

Spectral and

Space

Efficiency

Mutually

Exclusive

Point of Flux:

Reconfigurable?

Active?

Adaptive?

More Bands?

2010?



But More Spectrum is needed and coming

• More and more spectrum to be made available

• FCC Broadband plan promises another 300MHz by 2015 & 500MHz by 2020 (10 bands)

• Ofcom UK promises 500MHz by 2015

• LTE Advanced aligned with this multi-band concept (band bonding)

• More Antennas needed – Where we are positioned?

900 18002G

2100900 18003G

2600900 1800 2100800 4G

2600900 1800 2100800700 1500 2300White Space Tomorrow?

900 2G

Space Efficiency

Techniques



LTE-AWS

cdma1900

cdma800

LTE700

700/850/1900 Combiners

700/850/1900Combiners


LTE(AWS) Remote Head Solution shown

Quintel Product Applications for LTESpace Efficiency in a Multi-Band world


AWS

PCS1900

LTE700

800/850 Service

GSM900UMTS2100 GSM1800T

x/R

x

Tx

/Rx

Tx

/Rx

Tx

/Rx

Tx

/Rx

Tx

/Rx

Tx

/Rx

Tx

/Rx

Tx

/Rx

Optional 800/2600 Combiners

Optional Band Combiners

Optional TMAs

LTE800

LTE2600

9/18/21

GSM900

LTE800

(790-862MHz)

LTE2600

Tx

/Rx

Optional 900/1800/2100 Combiners

8/26

GSM1800UMTS2100

Space Efficiency

Techniques



MIMO Engineering & InnovationBack to Space Diversity to help Spectral Efficiency?

Quintel Dualband 4 Port Antennas(698-894MHz/1710-2170MHz)

6x Independent Tilts

LTE-AWS

UMTS

850

GSM1900

GSM850

LTE700

UMTS1900









4xn MIMO (LTE700 & LTE-AWS)Hybrid Space+Polz Diversity (GSM & UMTS)

LTE(AWS) Remote Head Solution shown, as an example of avoiding

AWS/850 diplex-combining.

• In US, most sites are 2x Antennas per sector.

• Quintel product allows initial 2x2 MIMO with

either:

– Conventional X-Pol only, or

– Spatially Separated X-Pols

• Quintel offering also support to upgrade to 4x4

MIMO on 700 and AWS bands

• Quintel maintains independent tilt for all

services also

• Patented technique and application.



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(-4

5o)

Ph

ase

Sh

ifte

rs T R T R

Tx/Rx2Tx/Rx1

Phase Slope across array (=tilt)

(proportional to)

Phase differential at corp feed inputs

+45 -45

Uplink/Downlink Independent TiltSpace & Spectral Efficiency

T R T R

LTE eNB

T R T R

• Uplink is normally “Coverage” limited and

• Downlink is normally “Interference” limited

• Uplink and Downlink are conventionally tilted as one

• A Dichotomy?

• Phase Shifting could be applied as part of (within) a

modified RRU.

• Can add other bands (within bandwidth of array) with

independent tilt as required from same array.

• Can also add other arrays for further bands.

LTE Downlink (5o)

LTE Uplink (3o)

Cell Boundary



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(-4

5o)

Ph

ase

Sh

ifte

rs T R T R T R T

Dynamic

Beamforming for

LTE Uplink

Independent Static

Tilt for LTE

Downlink

+45 -45

LTE eNB

T R T R

RxD3RxD4

R

Downlink Independent Tilt with Uplink BeamformingSpace & Spectral Efficiency

Tx/Rx2Tx/Rx1

• Same configuration as previous slide, but now

connecting both differential Rx pairs from +45 and -45

arrays to 4-way Maximal Ratio Combiner (MRC) at the

base station, rather than usual 2-way MRC.

• MRC algorithm simply applies weights and phase

delays to the 4x Rx inputs to maximize C/I, and will do

this on a per channel (per user) basis at baseband.

• Applying phase delays to within each of the Rx

differential pairs is simply creating a coherent beam

(tilt) toward/from the user.

• And applying phase/weights between +45 and -45 is

then standard 2-way Rx diversity.

LTE DownlinkLTE Uplink (Beamforming)



Antenna Innovation: Digital RANMoving to the Smarter Antenna

Present:

Remote Radio Head

Optical F

ibre

Sta

ndard

Ante

nna

20W PA

RRUBB-RF

Baseband

Server

Pow

er

Div

idin

g N

etw

ork

RE

T

Past:

Conventional BTS

Sta

ndard

Ante

nna

BTS

40W PA

Pow

er

Div

idin

g N

etw

ork

RE

T

BB-RFS

mart

Ante

nna

Baseb

an

d/D

AC

/RF

Sta

ges

Optical F

ibre

Future?:

Active Antenna

Optical F

ibre

Quin

tel

Ante

nna

2x10W PAs

RRU

Quin

tel

Corp

ora

te F

eed

Netw

ork

BB-RF

Baseband

ServerBaseband

Server

Innovation:

Quintel

Multi-Band Capable

Offers Active/Smart antenna features

Completely Passive

Spectral Efficiency Techniques



Antenna Innovation: Digital RANSome Quintel Advanced Patented (Digital) Applications

• Multi dimensional applications covering

• Optimisation of different access technologies in same freq band

• Optimising individual RF channels within same standard

• Enhancing cell throughput on network or cluster basis.

• All delivered through a single passive antenna

Spectral Efficiency

Techniques



Quintel Intelligent Passive AntennaThe “Smarter” Antenna

G900

G/L1800

L800

U2100

Active 2100

Antenna

Active 800

Antenna

Active 1800

Antenna

Passive 900

Band Antenna

Smart

Spectral Efficiency

Techniques

G900

G/L1800

L800

U2100

800/2100 Dual-

Band Antenna

900/1800 Dual-

Band Antenna

RRH

RRH

Conventional

Space Efficiency

Techniques

G900

G/L1800

L800

U2100

RRHRRH

Quintel

8-Port Antenna

Smarter

Space Efficiency

Techniques

Spectral Efficiency

Techniques



What about 4x4 MIMO?Ericsson MIMO Trials, Ericsson Review Jan 2010

+

Gain

Peak

Cell Edge

Average

Early 4xn MIMO trials may suggest that 4x Spatial Mux for SU-

MIMO is very rare in the radio channel, and it may be more

efficient to use 4x Radios as MU-MIMO or as 2x Spatial Mux

with some Beamforming....as introduced in 3GPP Rel 9/10

Weak performance for 3x or 4x Rates



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(-4

5o)

LTE800

4xTx/Rx

+45A +45B -45A -45B

Beamforming

in Elevation

across each

A&B ports

Spatial

Multiplexing up

to Rank 2 across

+45 and -45 BF

pairs

Dynamic

Beamform/Tilting

for LTE800

Interference

UE

• Quintel A&B ports can be considered as a first order

beamfomer input (we just change phase) but in

Elevation (First Order = 1 mainlobe+1 null = tilt)

• All literature to date considers Azimuthal Beamforming

delivered by multiple columns of arrays.

Quintel Elevation Beamforming AntennaThe “Smarter” Antenna

LTE (10MHz) Throughput vs. Distance Scatter Plot (Central Cells/Int Tilts)

(Mech Tilt = 3o, Elec Tilt=2

o, Bin Size = 10m, Boresight +/- 30

o)

Sites without Traffic EDT=7

0

10

20

30

40

50

60

0 100 200 300 400 500

Distance (m)

Th

rou

gh

pu

t (M

bp

s)

Original Throughput

Optimised Throughput



What’s a Dynamic Network?

Now - Standard RET

Tilt change every few months

Long term (underlying) variations in traffic and topology

Self Optimizing Network (SON) - Standard RET

Tilt change every few minutes at peak cycling

Short term variations in traffic and topology

Software Reconfigurable Networks

Quintel Innovation: Cell Tilt Sweeping

Tilt changes many time per second

Exploits Multi-User Scheduling Diversity; needs network synchronisation

(Opportunistic Beamforming technique)

Quintel Innovation: Beamforming in Elevation/per user tilting

Tilt or beamform change every TTI

Logically the same as MIMO Beamforming but in Elevation

(Optimal Beamforming technique)



LTE needs independent tilting to legacy servicesLTE is optimised with greater tilts (even for same traffic)

Global Metric for Cluster (cell edge areas):

Integrating over entire CDF for Cell

Edges, taken as the 90% percentile of

subscribers, then by interpolation the

Average Cell Edge Data Rate Throughput

per User has increased by 26.2%

>26% Increase in

throughput at

cell edges

Ind Tilt Network Throughputs:

86.8% Subs > 2Mbps

Independent Tilt Case

Common Tilt Network Throughputs:

79.1% Subs > 2Mbps

Common Tilt Case

LTE Optimised with

greater Tilts than for

CDMA1x

CDMA

LTE

http://www.symena.com/index.html



Site 1:

Time Varying TiltSite 2: Time Varying Tilt

(in anti-phase to Site 1)

The Cell Edge Sweeping ConceptThe “Smarter” Network?

• LTE has more robust link budget than 2G/3G

• LTE can be tilted more aggressively than 2G/3G for

same coverage

• More tilt = better network C/I = improved throughputs

• However, this means we have “unused tilt range”

• How can this be exploited?

• A whole loci of tilt combinations in a cluster can

maintain coverage

• By varying tilt synchronously over a cluster we can

move the cell edges around and maintain coverage

• In turn, no users “dwell” at cell edges and through

Scheduling are serviced during optimal C/I conditions

• We are introducing additional C/I variation to cell edge

users to make Scheduling more efficient.

(Ec / Io) T=0

Ec/ Io (dB) >=24

Ec/ Io (dB) >=23

Ec/ Io (dB) >=22

Ec/ Io (dB) >=21

Ec/ Io (dB) >=20

Ec/ Io (dB) >=19

Ec/ Io (dB) >=18

Ec/ Io (dB) >=17

Ec/ Io (dB) >=16

Ec/ Io (dB) >=15

Ec/ Io (dB) >=14

Ec/ Io (dB) >=13

Ec/ Io (dB) >=12

Ec/ Io (dB) >=11

Ec/ Io (dB) >=10

Ec/ Io (dB) >=9

Ec/ Io (dB) >=8

Ec/ Io (dB) >=7

Ec/ Io (dB) >=6

Ec/ Io (dB) >=5

Ec/ Io (dB) >=4

Ec/ Io (dB) >=3

Ec/ Io (dB) >=2

Ec/ Io (dB) >=1

Ec/ Io (dB) >=0

Ec/ Io (dB) >=-1

Ec/ Io (dB) >=-2

Ec/ Io (dB) >=-3

Ec/ Io (dB) >=-4

Ec/ Io (dB) >=-5

Ec/ Io (dB) >=-6

(Ec / Io) T=0

Ec/ Io (dB) >=24

Ec/ Io (dB) >=23

Ec/ Io (dB) >=22

Ec/ Io (dB) >=21

Ec/ Io (dB) >=20

Ec/ Io (dB) >=19

Ec/ Io (dB) >=18

Ec/ Io (dB) >=17

Ec/ Io (dB) >=16

Ec/ Io (dB) >=15

Ec/ Io (dB) >=14

Ec/ Io (dB) >=13

Ec/ Io (dB) >=12

Ec/ Io (dB) >=11

Ec/ Io (dB) >=10

Ec/ Io (dB) >=9

Ec/ Io (dB) >=8

Ec/ Io (dB) >=7

Ec/ Io (dB) >=6

Ec/ Io (dB) >=5

Ec/ Io (dB) >=4

Ec/ Io (dB) >=3

Ec/ Io (dB) >=2

Ec/ Io (dB) >=1

Ec/ Io (dB) >=0

Ec/ Io (dB) >=-1

Ec/ Io (dB) >=-2

Ec/ Io (dB) >=-3

Ec/ Io (dB) >=-4

Ec/ Io (dB) >=-5

Ec/ Io (dB) >=-6



The Cell Edge Sweeping Concept Initial Simulator Results

Static C/I Experienced

(Ec / Io) T=0

Ec/ Io (dB) >=24

Ec/ Io (dB) >=23

Ec/ Io (dB) >=22

Ec/ Io (dB) >=21

Ec/ Io (dB) >=20

Ec/ Io (dB) >=19

Ec/ Io (dB) >=18

Ec/ Io (dB) >=17

Ec/ Io (dB) >=16

Ec/ Io (dB) >=15

Ec/ Io (dB) >=14

Ec/ Io (dB) >=13

Ec/ Io (dB) >=12

Ec/ Io (dB) >=11

Ec/ Io (dB) >=10

Ec/ Io (dB) >=9

Ec/ Io (dB) >=8

Ec/ Io (dB) >=7

Ec/ Io (dB) >=6

Ec/ Io (dB) >=5

Ec/ Io (dB) >=4

Ec/ Io (dB) >=3

Ec/ Io (dB) >=2

Ec/ Io (dB) >=1

Ec/ Io (dB) >=0

Ec/ Io (dB) >=-1

Ec/ Io (dB) >=-2

Ec/ Io (dB) >=-3

Ec/ Io (dB) >=-4

Ec/ Io (dB) >=-5

Ec/ Io (dB) >=-6

(Ec / Io) T=0

Ec/ Io (dB) >=24

Ec/ Io (dB) >=23

Ec/ Io (dB) >=22

Ec/ Io (dB) >=21

Ec/ Io (dB) >=20

Ec/ Io (dB) >=19

Ec/ Io (dB) >=18

Ec/ Io (dB) >=17

Ec/ Io (dB) >=16

Ec/ Io (dB) >=15

Ec/ Io (dB) >=14

Ec/ Io (dB) >=13

Ec/ Io (dB) >=12

Ec/ Io (dB) >=11

Ec/ Io (dB) >=10

Ec/ Io (dB) >=9

Ec/ Io (dB) >=8

Ec/ Io (dB) >=7

Ec/ Io (dB) >=6

Ec/ Io (dB) >=5

Ec/ Io (dB) >=4

Ec/ Io (dB) >=3

Ec/ Io (dB) >=2

Ec/ Io (dB) >=1

Ec/ Io (dB) >=0

Ec/ Io (dB) >=-1

Ec/ Io (dB) >=-2

Ec/ Io (dB) >=-3

Ec/ Io (dB) >=-4

Ec/ Io (dB) >=-5

Ec/ Io (dB) >=-6

Static Network

Cell edge conditions ~ -3dB

Scheduled Rate ~2Mbps

Tilt sweeping Network

Peak Cell edge cond’s~ +3dB

Scheduled Rate ~7Mbps

1.6x Total Cell and 3x Cell Edge Throughput Increases

Cell Edge region

(<15% Area)

Cell Edge region

(<15% Area)

Peak C/I Experienced

C/I Experienced in Static Tilts



Summary

• Antennas are bound by Physics: Maxwell’s Laws

• Slow evolution in innovation

• Data Explosion = More Spectrum bands and need for Spectral Efficiencies

• Where next: Active, Adaptive array, or Multi-Banding

• Can we have both Spectral and Space Efficiencies?

• Multi-Banding is key to scaling for the future

• Passive Platform delivering Space, Spectral, Cost and Reliability Efficiencies

• Dynamic Networks: RET, SON, Beamforming, Tilt Sweeping

• Innovation is about thinking laterally about problems rather than throwing

brute force at the problem; marrying the network with the antenna



Thank You!Dave Barker+44 7958 418816

[email protected]

When wireless is pushed to the limitthe answer isn’t more of the same

The answer is

more innovation

mailto:[email protected]

David Barker - Quintel - Base Station Antenna Innovation

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